Division of Tumor and Cellular Biochemistry, Department of Medical Sciences, University of Miyazaki, Miyazaki, Japan.
Division of Hepato-biliary-pancreas Surgery, Department of Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.
Anticancer Res. 2022 Apr;42(4):1763-1775. doi: 10.21873/anticanres.15653.
BACKGROUND/AIM: Pancreatic ductal adenocarcinoma (PDAC) is one of the most common cancers worldwide, with a poor prognosis. Owing to the difficulty of early diagnosis, the aim of this study was to isolate biomarkers from extracellular vesicles (EVs) that can lead to early diagnosis.
EVs in the culture supernatant were isolated from a pancreatic cancer cell line (PK-1) and expanded by using two-dimensional gel electrophoresis, and protein identification from each spot was performed by using matrix-assisted laser desorption ionization mass spectrometry. The identified proteins were classified and compared with previously reported results for EVs from murine pancreatic cancer PAN02 cells, and their expression specificity was examined using PDAC cell lines and patient-derived PDAC tissues. In addition, the significance of selected biomarker(s) was examined based on the changes in biomarkers in the blood EVs of PDAC patients after surgery.
We found that the ITGA6A splice variant was predominantly expressed in several pancreatic cancer cell lines and blood EVs from patients with PDAC, whereas the ITGA6B splice variant was predominantly expressed in EVs from the blood of normal volunteers. In the expression pattern of ITGA6 in EVs from blood samples of two PDAC patients before and after resection surgery, the expression of ITGA6A in EVs significantly decreased after surgery and increased several months before clinical recurrence. Furthermore, the increased expression of ITGA6A in EVs occurred much earlier than that of CA19-9.
Determination of ITGA6A expression in blood EVs in PDAC patients could be a useful blood marker for the early diagnosis of PDAC recurrence.
背景/目的：胰腺导管腺癌（PDAC）是全球最常见的癌症之一，预后较差。由于早期诊断困难，本研究旨在从细胞外囊泡（EVs）中分离出能够导致早期诊断的生物标志物。
从胰腺癌细胞系（PK-1）的培养上清液中分离 EVs，并用二维凝胶电泳进行扩增，并通过基质辅助激光解吸电离质谱对每个斑点的蛋白质进行鉴定。将鉴定的蛋白质进行分类，并与先前报道的来自鼠胰腺癌细胞 PAN02 的 EV 结果进行比较，并用 PDAC 细胞系和患者来源的 PDAC 组织检查其表达特异性。此外，还根据 PDAC 患者手术后血液 EV 中生物标志物的变化，检查了选定生物标志物的意义。
我们发现，ITGA6A 剪接变体在几种胰腺癌细胞系和 PDAC 患者的血液 EV 中均有较高表达，而 ITGA6B 剪接变体在正常志愿者血液 EV 中则有较高表达。在两名 PDAC 患者手术前后血液样本 EV 中 ITGA6 的表达模式中，手术后 EV 中 ITGA6A 的表达显著降低，而在临床复发前数月则升高。此外，EV 中 ITGA6A 的表达增加早于 CA19-9 的表达增加。
在 PDAC 患者的血液 EV 中测定 ITGA6A 的表达可能是 PDAC 复发的有用血液标志物。
